Thermoplastic polyesters, e.g., poly(ethylene terephthalate) or PET, have many commercial applications for use in fabrics, films, containers, and the like, due to their mechanical strength, flexural characteristics, clarity, thermal stability, impact strength, and permeability characteristics. PET can also be used as an engineering plastic, wherein compounded glass filled compositions are injection molded for electrical, electronics, or automotive applications, etc. During injection molding high crystallization temperatures (Tc) are needed in order to get short cycle times, low warpage and molded articles that have sufficient crystallinity. Crystallinity is desirable in engineering applications due to the higher thermal and mechanical stability associated with crystallinity.
In spite of PET's many desirable characteristics, PET is known as a slow crystallizing polymer. It is known that PET crystallization temperature or Tc strongly depends on the diethylene glycol content incorporated into the PET chains during the early stages of polymerisation. Prior art methods to increase the rate of crystallization of PET have been directed toward incorporation of inorganic compounds, salts, and polyolefins into PET to act as nucleation aids. The use of the nucleating agents, while often have a desired effect on the crystallization rate, sometimes have adverse consequences, such as lowering the mechanical properties or its molecular weight There exists a need in the art for a method to accelerate the rate of crystallization of PET in compositions without the limitations of the prior art.